Electrical sound tuning and production system



Jan. 19, 1937. A. McL. NICOLSON ELECTRICAL SOUND TUNING AND PRODUCTION SYSTEM Original Filed Oct. 18, 1933 2 Sheets-Sheet l AMP. 4

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RELAY FILTER n 5 k W M o l 4 P m 2 M v m fw A W MA P- V 1; MB m X c 0 c h w 2/ m A Y Y UH M U E E R R g R R TD E E u #7 u E W F F E in CU E m R H CF B W a m UTA Jan. 19, 1937. A. McL. NICOLSON ELECTRICAL SOUJD TUNING AND PRODUCTION SYSTEM 2 Sheets-Sheet 2 Original Filed Oct. 18, 1933 FIE-1:

Patented Jan. 19, 1937 UNITED STATES ELECTRICAL SO UND TUNING AND PRODUCTION SYSTEM I Alexander McLean Nicolson, New York, N. Y., as-

signor to Communication Patents, Inc., New

York, N. Y., a. corporation of Delaware Application October 18, 1933, Serial No. 694,100 Renewed June 17, 1936 16 Claims.

This invention relates to the production of signals or sounds from oscillators, recorded or synthetic sound tracks controlled manually or directly from a sound-electrical translator, such as a microphone, and is particularly adaptable for indicating the proper or improper pitch of sound waves of musical instruments or of the voice.

With such instruments as pianos, which are used considerably or which are subject to changes in temperature or conditions of humidity, frequent tuning is necessary. Tuning is usually accomplished by a person using his ear as the indicator of the desired pitch. With the present invention this is accomplished mechanically, eliminating the human susceptibility to err. Furthermore, the invention is suitable for the teaching of singing whereby any improper pitch is indicated as such or is corrected by the production of the true tone at the time of error.

In cases Where the tiue tones are produced synthetically, the apparatus is believed to be especially suited for other purposes, such as for the playing of music similar to that from electric pianos or organs. Furthermore, it can be employed as a "prompter during rendition of a selection by producing the correct note at the proper time.

An object of the invention is to produce electrically notes or tones of any desired frequency, form and arrangement.

Another object of the invention is to indicate or produce the proper tones or musical notes during a recitation when the wrong tones or notes are played or sung.

A further object of the invention is to enable the adjustment of frequency instruments to any required degree, the proper or improper tuning to be visually or aurally indicated.

The invention will be more fully understood by reference to the following description read in conjunction with the accompanying drawings in which:

Fig. 1 is a diagrammatic representation of a tuner or indicator of pitch in accordance with the invention;

Fig. 2 is a similar representation of a tuner or voice indicator which produces the proper tones when the improper tones are produced;

Fig. 3 is a graph representing the tuning of the band pass filters used in the invention;

Fig. 4 is a diagrammatic drawing of a modification of Fig. 2 which produces any form of tone desired, and

Fig. 5 is a diagrammatic drawing of a system for producing orchestrations or the tones from any single instrument.

Referring to Fig. I particularly, a plurality. of filters 5 have a common input through a plural winding transformer 6, and a common output through plural winding transformer 1. Transformer 6 is supplied from an amplifier 4 connected to a microphone 8. Transformer 1 feeds a relay to, which may control a visual signal in the form of a lamp II or an aural signal in the form of a bell alarm l2 or both. The relay l0 may be self-contained or may be supplied from a. volt alternating current source.

A similar circuit is shown in Fig. 2 in which a plural winding input transformer l5 and a plural winding output transformer I6 are interconnected by a plurality of filters 18 with their corresponding relays I9 and oscillators 20, respectively. Input transformer I5 is connected to an amplifier 22 fed from a microphone 23, while output transformer l6 feeds an amplifier 24 connected to a sound reproducing device 25.

The operations of the systems of Figs. 1 and 2 are similar, except that the system of Fig. l supplies only a visual or aural indication at the time a right or wrong frequency is supplied at the microphone 8, while the system of Fig. 2 indicates the wrong frequency input at microphone 23 by producing the correct tone at the sound reproducer 25. The filters 5 of Fig. 1 and N3 of Fig. 2 may both be tuned to pass the correct frequencies in a tonal scale, or the filters 5 pass the correct frequencies, while filters l8 pass the incorrect frequencies of the scale. That is, these are band pass filters tuned to the frequency which it is desired to have operate the relay It] or relays l9 and their respective signaling devices I I, I 2 or 25. The oscillators 20, however, of Fig. 2, are tuned to the frequencies which are properly desired as output frequencies, such as the tones of the piano or the vocal range of fundamental and harmonic frequencies. If either system is used for piano tuning, then approximately 88 channels or filters are required to take care of the average key board, while for voice only apto pass the tone or frequency scale desired, these frequencies operating the signaling device to indicate these proper tones. That is, the filters pass all the frequencies between two permissible limits. However, these filters and filters l8 of person is singing the proper tones in the microphone 23, there will be no signals produced at 25. Let a person sing off key in either direction, however, then the apparatus produces the proper frequency. As shown in Fig. 3, the tuning of the filters varies as the freuency bands between tones vary between the ends of the musical scales. These filters are constructed in this manner to indicate off-key variations, and may be adjusted to indicate any degree thereof up to one quarter of a tone in either direction. The filters may be made as selective as comparable with the instrument with which it is to be used or the use to which it is to be put.

It is obvious from the above description that the tuning of any frequency scaled instrument is accomplished solely by impressing on the microphone the tones of the instrument and noting and adjusting them to the desired pitch, which is indicated either negatively or positively when the adjustment is correct.

Referring to Fig. 4, which is a refined embodiment of Fig. 2, since it is possible with this systam to produce the tones of any instrument or quality of voice desired, a source of light such as an are or electrical discharge is produced between circular electrode rails 30, supplied from a source of potential 3| under control of a rheostat 82. The driving force for an are created across the rails is obtained from a solenoid winding shown at 35, supplied from a source of potential 34 under control of a rheostat 35. Similar arc systems are disclosed in my Patent No. 1,803,278 of June 14, 1932 and copending application Serial No. 568,012, filed October 10, 1931, now Patent No. 1,962,610, granted June 12. 1934. Light from the moving arc is focused by a lens 35 on to a composite disc 39, upon which are placed sound tracks or templets of the sound desired. That is, these recordings are on a transparent medium similar to the sound track on him and are arranged so that light passes through all of them simultaneously in a line along a radial direction. It is to be understood that the disc may be opaque and the system operate by reflected light from the sound tracks. These discs are made interchangeable to permit the selection of various types of tones. The emerging light through the disc 39 is focused by a lens 40 on to a cathode 4| of a photo sensitive device, the cathode being in the form of insulated concentric rings of photosensitive material. The cathode is contained within an envelope 42, the envelope also containing a, ring anode 43 to complete the photosensitive device. Each concentric ring of the cathode is connected through switches 50, ground connections 55 and iii, a potential source 5| and an impedance 52, to the anode 43. Across the impedance 52 is connected an amplifier 53, feeding a sound reproducing source 54.

The Just described multiple circuits are con trolled by a plurality of magnetic relays 56 connected to a corresponding plurality of filters 51. It is to be understood that these relays may be thermionic biased tubes operating in a well known manner. The filters 51 are fed from a plural winding transformer 58, the primary of which is connected to an amplifier 59 fed from a microphone 60. Any signals passing through the filters will cause the relays to actuate the switches 50 and thereby connect the respective ring of the cathode to the amplifier 53 and sound reproducer 54. It is obvious, therefore, that if any tone is desired at 54, it is only necessary to connect that tone switch and the tone will be produced by the movement of the light from the scanning are as it passes over the sound track on the disc 39. Of course, it is realized that sumcient tones on one disc for a complete scale may be impractical and provision is made for similar systems such as shown at B2, B3, 54 and 65, which may be connected to the transformer 58 in the same manner as the one just described.

It is thus seen that many tones, or all that are required for instruments or for the voice range, can be easily produced in this manner with a light source common to all systems. Furthermore, this system lends itself to the correction of a singer during a performance by having a recording on the disc of the singer's characteristic tones and having the proper note produced by the system when the singer errs. Ordinariiy the filters 51 are tuned to the frequency bands lying between the dotted lines as shown in Fig. 3, a slight separation being made at these points. This will produce single note prompting. If the filters are tuned, however, to the frequcncies between the solid lines as shown, then a continuous prompter is provided and one which will faithfully follow the originator. Furthermore, in this manner the recording of one instrument may be combined with the original of another such as a violin with a piano recording for accompaniment since the selection of the notes is made on a frequency basis. Also a recorded accompaniment may be had with a vocal selection.

In Fig. 5 the are system shown at 10 is similar to the one shown in Fig. 4; the lenses 1i and 12 are similar to lenses 38 and 52 of Fig. 4; while the discs 13 and 14 and lenses 15 and 18 are counterparts of discs 39 and B3 and lenses 40 and 54 of Fig. 4, respectively. Similarly, the photoelectric devices 18 and 19 are constructed and operate in the same manner as devices 42 and B5 of Fig. 4, while similar photo cell circuits connect their output to amplifier and sound reproducing device 8|. The difference between the two circuits is in the manner of actuation of the sound control circuits which in Fig. 5 is a plurality of manually operated keys 83. These keys may be arranged as a piano or organ manual key board, and by the use of various types of sound tracks on the discs 13 and 14, representing various instruments or voices, different themes or combinations may be produced at the reproducer 81 for single melodies or orchestrations.

The advantages of the above sound tuning and production systems are many in that they remove the human element in the art of tuning instruments having a frequency scale. It is not only applicable to musical instruments, but to frequency indicators, such as meters, etc. It is particularly valuable, however, to indicate to singers or musicians when the incorrect tone is sung or played. For instance, for teaching the playing of instruments such as the violin and slide trombone where the position of the fingers or of the slide determines the pitch or note and no guide is provided therefor, an indicating device of this type is of particular value.

The system is also advantageous for producing synthetic music and it is believed that the novel arrangement of a moving light source and stationary sound tracks is particularly suitable for this purpose.

What is claimed is:

1. In combination, means for translating sound waves into corresponding electrical currents, means for distinguishing certain of said currents on the basis of the frequencies thereof, said certain currents being a series of frequency groups, means operative by the currents passed by said last mentioned means, and means ener- Is gized by said operated means for passage of said currents.

2. In combination, means for translating sound waves into corresponding electrical currents, means for discriminating between alternate groups of frequencies of said currents, said groups forming a series, means operated by said currents passed by said last mentioned means, and means energized by said operated means for indicating the passage of said currents.

3. In combination, means for translating sound Waves into corresponding electrical currents, means for uniformly discriminating between certain frequencies of a serial tone scale and frequencies intermediate said certain frequencies, means operative by currents passing through said last mentioned means, and means actuated by said operated means for indicating the passage of said currents.

4. In combination, means for translating sound waves into corresponding electrical currents, means for discriminating between the frequencies of said currents in a serial tone scale, means for generating sound waves having particular frequencies in accordance with the frequency passed by said discriminating means and means for actuating said last mentioned means by the electrical currents passed by said discriminating means.

5. In combination, means for translating sound waves into corresponding electrical currents, means for generating electrical currents having frequencies corresponding to certain sound waves, a sound reproducing device connected to said current generating means, and means intermediate said current generating means and said translator for transmitting to said generating means electrical currents having predetermined frequencies, said currents operating said generating means in accordance with the frequency thereof.

6. In combination, means for producing a moving light beam, a plurality of sound tracks scanned by said beam, a photosensitive device upon which said light beam is impressed after modulation by said sound tracks, means for transforming electrical currents into sound waves, and means for connecting the output of said photosensitive device with said last mentioned means, said means including a plurality of circuit contactors.

7. In combination, means for providing a moving light beam, sound records upon which said light beam is impressed, a photosensitive device affected by said light beam after modulation by said sound records, means for translating electrical currents into sound waves, a plurality of circuits interconnecting said photosensitive device and said last mentioned means, a device for translating sound waves into electrical currents, and means intermediate said device and said plurality of circuits for passing currents of certain frequencies to operate said circuits.

8. In combination, means for translating sound waves into electrical currents, means for discriminating between definite frequencies of said currents, means for translating electrical currents into sound waves, means for producing electrical currents corresponding to a recorded sound wave, and means operative by the current passed through said frequency discriminating means for operating said current to sound translator in accordance with the frequencies transmitted through said discriminating means.

indicating the 9. In a sound reproducing system, an electrical current to sound translator, a light to electrical current translator, a plurality of sound recordings having a plurality of definite frequencies for each recording, means for producing a light beam for scanning all of said recordings simultaneously, and means for connecting said light to electrical current translator with said current to sound translator upon the initiation of certain predetermined frequencies correlated with said recorded frequencies for reproducing certain of said recorded frequencies.

10. A method of producing synthetic sound comprising modulating a moving light beam with a plurality of sound recordings simultaneously, simultaneously generating a plurality of electrical currents corresponding to said light modulations and translating said electrical currents into sound in a definite order.

11. In a sound reproducing system, a light to electrical current translator, a moving source of light, a stationary plurality of tone forms intermediate said translator and light source for modulating said light, an electrical current to sound translator, and means for interconnecting said translators to reproduce at least one of said tone forms.

12. A sound reproducing system in accordance with claim 11 in which light is an ionized field.

13. In combination, a sound to electrical current translator, an electrical current to sound translator, means connected to said sound to current translator for producing electrical currents corresponding to certain sounds impressed upon said first translator, and means for actuating said electrical current to sound translator when certain other sounds are impressed upon said first translator.

14. A method of producing synthetic sound from an electrical current generating device comprising simultaneously modulating a plurality of moving light beams into a plurality of modulated beams from a corresponding plurality of sound recordings, simultaneously impressing said plurality of light modulated beams on to said electrical current generating device, and translating the output of said device into sound in a certain order.

15. In apparatus for the production of synthetic sound, the combination of means for producing a plurality of moving light beams from a single source, a plurality of sound recordings arranged to simultaneously intercept said beams for producing a plurality of separately modulated light beams, a photosensitive device for translating all of said plurality of beams into electric currents simultaneously, an electrical current to sound translator, and relays for connecting said translator to said photosensitive device in a certain manner.

16. In a sound producing system, a plurality of tone forms, means for producing electrical currents corresponding to said forms simultaneously, means for translating said currents into sound, and means actuated by a voice having substantially the same frequencies as said tone forms for connecting said current producing means and path propagated by a magnetic said moving source of said translating means in the order of voice frequency production.

ALEXANDER MCLEAN NICOLSON. 

